Crystal Palace, madrid

In Madrid's Retiro Park stands the Palacio de Cristal, a historic 19th-century greenhouse that now serves as an exhibition space for contemporary art. The building is designed in the shape of a Greek cross and is made almost entirely of glass set in an iron frame on a brick base decorated with ceramic tiles. Its dome gives the structure a height of more than 72 feet (22 meters). Architecturally, the building recalls the pioneers of glass-and-iron construction in England. Originally used as the main venue of the 1887 Philippine Exposition, it housed living plants at the time. Today the Palacio de Cristal belongs to the Reina Sofía Museum and hosts rotating art exhibitions, while retaining its original appearance.